// Copyright 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "url/gurl.h"

#include <stddef.h>

#include <algorithm>
#include <ostream>

#include "base/logging.h"
#include "base/strings/string_piece.h"
#include "base/strings/string_util.h"
//#include "base/trace_event/memory_usage_estimator.h"
#include "url/url_canon_stdstring.h"
#include "url/url_util.h"

#ifdef WIN32
#include <windows.h>
#else
#include <pthread.h>
#endif

namespace {

static std::string* empty_string = NULL;
static GURL* empty_gurl = NULL;

#ifdef WIN32

// Returns a static reference to an empty string for returning a reference
// when there is no underlying string.
const std::string& EmptyStringForGURL()
{
    // Avoid static object construction/destruction on startup/shutdown.
    if (!empty_string) {
        // Create the string. Be careful that we don't break in the case that this
        // is being called from multiple threads. Statics are not threadsafe.
        std::string* new_empty_string = new std::string;
        if (InterlockedCompareExchangePointer(
                reinterpret_cast<PVOID*>(&empty_string), new_empty_string, NULL)) {
            // The old value was non-NULL, so no replacement was done. Another
            // thread did the initialization out from under us.
            delete new_empty_string;
        }
    }
    return *empty_string;
}

#else

static pthread_once_t empty_string_once = PTHREAD_ONCE_INIT;
static pthread_once_t empty_gurl_once = PTHREAD_ONCE_INIT;

void EmptyStringForGURLOnce(void)
{
    empty_string = new std::string;
}

const std::string& EmptyStringForGURL()
{
    // Avoid static object construction/destruction on startup/shutdown.
    pthread_once(&empty_string_once, EmptyStringForGURLOnce);
    return *empty_string;
}

#endif // WIN32

} // namespace

GURL::GURL()
    : is_valid_(false)
{
}

GURL::GURL(const GURL& other)
    : spec_(other.spec_)
    , is_valid_(other.is_valid_)
    , parsed_(other.parsed_)
{
    if (other.inner_url_)
        inner_url_.reset(new GURL(*other.inner_url_));
    // Valid filesystem urls should always have an inner_url_.
    DCHECK(!is_valid_ || !SchemeIsFileSystem() || inner_url_);
}

GURL::GURL(GURL&& other) noexcept
    : spec_(std::move(other.spec_))
    , is_valid_(other.is_valid_)
    , parsed_(other.parsed_)
    , inner_url_(std::move(other.inner_url_))
{
    other.is_valid_ = false;
    other.parsed_ = url::Parsed();
}

GURL::GURL(base::StringPiece url_string)
{
    InitCanonical(url_string, true);
}

GURL::GURL(base::StringPiece16 url_string)
{
    InitCanonical(url_string, true);
}

GURL::GURL(const std::string& url_string, RetainWhiteSpaceSelector)
{
    InitCanonical(base::StringPiece(url_string), false);
}

GURL::GURL(const char* canonical_spec,
    size_t canonical_spec_len,
    const url::Parsed& parsed,
    bool is_valid)
    : spec_(canonical_spec, canonical_spec_len)
    , is_valid_(is_valid)
    , parsed_(parsed)
{
    InitializeFromCanonicalSpec();
}

GURL::GURL(std::string canonical_spec, const url::Parsed& parsed, bool is_valid)
    : spec_(std::move(canonical_spec))
    , is_valid_(is_valid)
    , parsed_(parsed)
{
    InitializeFromCanonicalSpec();
}

template <typename STR>
void GURL::InitCanonical(base::BasicStringPiece<STR> input_spec,
    bool trim_path_end)
{
    url::StdStringCanonOutput output(&spec_);
    is_valid_ = url::Canonicalize(
        input_spec.data(), static_cast<int>(input_spec.length()), trim_path_end,
        NULL, &output, &parsed_);

    output.Complete(); // Must be done before using string.
    if (is_valid_ && SchemeIsFileSystem()) {
        inner_url_.reset(new GURL(spec_.data(), parsed_.Length(),
            *parsed_.inner_parsed(), true));
    }
    // Valid URLs always have non-empty specs.
    DCHECK(!is_valid_ || !spec_.empty());
}

void GURL::InitializeFromCanonicalSpec()
{
    if (is_valid_ && SchemeIsFileSystem()) {
        inner_url_.reset(
            new GURL(spec_.data(), parsed_.Length(),
                *parsed_.inner_parsed(), true));
    }

#ifndef NDEBUG
    // For testing purposes, check that the parsed canonical URL is identical to
    // what we would have produced. Skip checking for invalid URLs have no meaning
    // and we can't always canonicalize then reproducibly.
    if (is_valid_) {
        DCHECK(!spec_.empty());
        url::Component scheme;
        // We can't do this check on the inner_url of a filesystem URL, as
        // canonical_spec actually points to the start of the outer URL, so we'd
        // end up with infinite recursion in this constructor.
        if (!url::FindAndCompareScheme(spec_.data(), spec_.length(),
                url::kFileSystemScheme, &scheme)
            || scheme.begin == parsed_.scheme.begin) {
            // We need to retain trailing whitespace on path URLs, as the |parsed_|
            // spec we originally received may legitimately contain trailing white-
            // space on the path or  components e.g. if the #ref has been
            // removed from a "foo:hello #ref" URL (see http://crbug.com/291747).
            GURL test_url(spec_, RETAIN_TRAILING_PATH_WHITEPACE);

            DCHECK(test_url.is_valid_ == is_valid_);
            DCHECK(test_url.spec_ == spec_);

            DCHECK(test_url.parsed_.scheme == parsed_.scheme);
            DCHECK(test_url.parsed_.username == parsed_.username);
            DCHECK(test_url.parsed_.password == parsed_.password);
            DCHECK(test_url.parsed_.host == parsed_.host);
            DCHECK(test_url.parsed_.port == parsed_.port);
            DCHECK(test_url.parsed_.path == parsed_.path);
            DCHECK(test_url.parsed_.query == parsed_.query);
            DCHECK(test_url.parsed_.ref == parsed_.ref);
        }
    }
#endif
}

GURL::~GURL()
{
}

GURL& GURL::operator=(const GURL& other)
{
    spec_ = other.spec_;
    is_valid_ = other.is_valid_;
    parsed_ = other.parsed_;

    if (!other.inner_url_)
        inner_url_.reset();
    else if (inner_url_)
        *inner_url_ = *other.inner_url_;
    else
        inner_url_.reset(new GURL(*other.inner_url_));

    return *this;
}

GURL& GURL::operator=(GURL&& other)
{
    spec_ = std::move(other.spec_);
    is_valid_ = other.is_valid_;
    parsed_ = other.parsed_;
    inner_url_ = std::move(other.inner_url_);

    other.is_valid_ = false;
    other.parsed_ = url::Parsed();
    return *this;
}

const std::string& GURL::spec() const
{
    if (is_valid_ || spec_.empty())
        return spec_;

    DCHECK(false) << "Trying to get the spec of an invalid URL!";
    return EmptyStringForGURL();
}

bool GURL::operator<(const GURL& other) const
{
    return spec_ < other.spec_;
}

bool GURL::operator>(const GURL& other) const
{
    return spec_ > other.spec_;
}

// Note: code duplicated below (it's inconvenient to use a template here).
GURL GURL::Resolve(const std::string& relative) const
{
    // Not allowed for invalid URLs.
    if (!is_valid_)
        return GURL();

    GURL result;
    url::StdStringCanonOutput output(&result.spec_);
    if (!url::ResolveRelative(spec_.data(), static_cast<int>(spec_.length()),
            parsed_, relative.data(),
            static_cast<int>(relative.length()),
            nullptr, &output, &result.parsed_)) {
        // Error resolving, return an empty URL.
        return GURL();
    }

    output.Complete();
    result.is_valid_ = true;
    if (result.SchemeIsFileSystem()) {
        result.inner_url_.reset(
            new GURL(result.spec_.data(), result.parsed_.Length(),
                *result.parsed_.inner_parsed(), true));
    }
    return result;
}

// Note: code duplicated above (it's inconvenient to use a template here).
GURL GURL::Resolve(const base::string16& relative) const
{
    // Not allowed for invalid URLs.
    if (!is_valid_)
        return GURL();

    GURL result;
    url::StdStringCanonOutput output(&result.spec_);
    if (!url::ResolveRelative(spec_.data(), static_cast<int>(spec_.length()),
            parsed_, relative.data(),
            static_cast<int>(relative.length()),
            nullptr, &output, &result.parsed_)) {
        // Error resolving, return an empty URL.
        return GURL();
    }

    output.Complete();
    result.is_valid_ = true;
    if (result.SchemeIsFileSystem()) {
        result.inner_url_.reset(
            new GURL(result.spec_.data(), result.parsed_.Length(),
                *result.parsed_.inner_parsed(), true));
    }
    return result;
}

// Note: code duplicated below (it's inconvenient to use a template here).
GURL GURL::ReplaceComponents(
    const url::Replacements<char>& replacements) const
{
    GURL result;

    // Not allowed for invalid URLs.
    if (!is_valid_)
        return GURL();

    url::StdStringCanonOutput output(&result.spec_);
    result.is_valid_ = url::ReplaceComponents(
        spec_.data(), static_cast<int>(spec_.length()), parsed_, replacements,
        NULL, &output, &result.parsed_);

    output.Complete();
    if (result.is_valid_ && result.SchemeIsFileSystem()) {
        result.inner_url_.reset(new GURL(result.spec_.data(),
            result.parsed_.Length(),
            *result.parsed_.inner_parsed(), true));
    }
    return result;
}

// Note: code duplicated above (it's inconvenient to use a template here).
GURL GURL::ReplaceComponents(
    const url::Replacements<base::char16>& replacements) const
{
    GURL result;

    // Not allowed for invalid URLs.
    if (!is_valid_)
        return GURL();

    url::StdStringCanonOutput output(&result.spec_);
    result.is_valid_ = url::ReplaceComponents(
        spec_.data(), static_cast<int>(spec_.length()), parsed_, replacements,
        NULL, &output, &result.parsed_);

    output.Complete();
    if (result.is_valid_ && result.SchemeIsFileSystem()) {
        result.inner_url_.reset(new GURL(result.spec_.data(),
            result.parsed_.Length(),
            *result.parsed_.inner_parsed(), true));
    }
    return result;
}

GURL GURL::GetOrigin() const
{
    // This doesn't make sense for invalid or nonstandard URLs, so return
    // the empty URL.
    if (!is_valid_ || !IsStandard())
        return GURL();

    if (SchemeIsFileSystem())
        return inner_url_->GetOrigin();

    url::Replacements<char> replacements;
    replacements.ClearUsername();
    replacements.ClearPassword();
    replacements.ClearPath();
    replacements.ClearQuery();
    replacements.ClearRef();

    return ReplaceComponents(replacements);
}

GURL GURL::GetAsReferrer() const
{
    if (!SchemeIsValidForReferrer())
        return GURL();

    if (!has_ref() && !has_username() && !has_password())
        return GURL(*this);

    url::Replacements<char> replacements;
    replacements.ClearRef();
    replacements.ClearUsername();
    replacements.ClearPassword();
    return ReplaceComponents(replacements);
}

GURL GURL::GetWithEmptyPath() const
{
    // This doesn't make sense for invalid or nonstandard URLs, so return
    // the empty URL.
    if (!is_valid_ || !IsStandard())
        return GURL();

    // We could optimize this since we know that the URL is canonical, and we are
    // appending a canonical path, so avoiding re-parsing.
    GURL other(*this);
    if (parsed_.path.len == 0)
        return other;

    // Clear everything after the path.
    other.parsed_.query.reset();
    other.parsed_.ref.reset();

    // Set the path, since the path is longer than one, we can just set the
    // first character and resize.
    other.spec_[other.parsed_.path.begin] = '/';
    other.parsed_.path.len = 1;
    other.spec_.resize(other.parsed_.path.begin + 1);
    return other;
}

bool GURL::IsStandard() const
{
    return url::IsStandard(spec_.data(), parsed_.scheme);
}

bool GURL::IsAboutBlank() const
{
    if (!SchemeIs(url::kAboutScheme))
        return false;

    if (has_host() || has_username() || has_password() || has_port())
        return false;

    if (path() != url::kAboutBlankPath && path() != url::kAboutBlankWithHashPath)
        return false;

    return true;
}

bool GURL::SchemeIs(base::StringPiece lower_ascii_scheme) const
{
    DCHECK(base::IsStringASCII(lower_ascii_scheme));
    DCHECK(base::ToLowerASCII(lower_ascii_scheme) == lower_ascii_scheme);

    if (parsed_.scheme.len <= 0)
        return lower_ascii_scheme.empty();
    return scheme_piece() == lower_ascii_scheme;
}

bool GURL::SchemeIsHTTPOrHTTPS() const
{
    return SchemeIs(url::kHttpScheme) || SchemeIs(url::kHttpsScheme);
}

bool GURL::SchemeIsValidForReferrer() const
{
    return is_valid_ && IsReferrerScheme(spec_.data(), parsed_.scheme);
}

bool GURL::SchemeIsWSOrWSS() const
{
    return SchemeIs(url::kWsScheme) || SchemeIs(url::kWssScheme);
}

int GURL::IntPort() const
{
    if (parsed_.port.is_nonempty())
        return url::ParsePort(spec_.data(), parsed_.port);
    return url::PORT_UNSPECIFIED;
}

int GURL::EffectiveIntPort() const
{
    int int_port = IntPort();
    if (int_port == url::PORT_UNSPECIFIED && IsStandard())
        return url::DefaultPortForScheme(spec_.data() + parsed_.scheme.begin,
            parsed_.scheme.len);
    return int_port;
}

std::string GURL::ExtractFileName() const
{
    url::Component file_component;
    url::ExtractFileName(spec_.data(), parsed_.path, &file_component);
    return ComponentString(file_component);
}

std::string GURL::PathForRequest() const
{
    DCHECK(parsed_.path.len > 0)
        << "Canonical path for requests should be non-empty";
    if (parsed_.ref.len >= 0) {
        // Clip off the reference when it exists. The reference starts after the
        // #-sign, so we have to subtract one to also remove it.
        return std::string(spec_, parsed_.path.begin,
            parsed_.ref.begin - parsed_.path.begin - 1);
    }
    // Compute the actual path length, rather than depending on the spec's
    // terminator. If we're an inner_url, our spec continues on into our outer
    // URL's path/query/ref.
    int path_len = parsed_.path.len;
    if (parsed_.query.is_valid())
        path_len = parsed_.query.end() - parsed_.path.begin;

    return std::string(spec_, parsed_.path.begin, path_len);
}

std::string GURL::HostNoBrackets() const
{
    // If host looks like an IPv6 literal, strip the square brackets.
    url::Component h(parsed_.host);
    if (h.len >= 2 && spec_[h.begin] == '[' && spec_[h.end() - 1] == ']') {
        h.begin++;
        h.len -= 2;
    }
    return ComponentString(h);
}

std::string GURL::GetContent() const
{
    return is_valid_ ? ComponentString(parsed_.GetContent()) : std::string();
}

bool GURL::HostIsIPAddress() const
{
    return is_valid_ && url::HostIsIPAddress(host_piece());
}

#ifdef WIN32

const GURL& GURL::EmptyGURL()
{
    // Avoid static object construction/destruction on startup/shutdown.
    if (!empty_gurl) {
        // Create the string. Be careful that we don't break in the case that this
        // is being called from multiple threads.
        GURL* new_empty_gurl = new GURL;
        if (InterlockedCompareExchangePointer(
                reinterpret_cast<PVOID*>(&empty_gurl), new_empty_gurl, NULL)) {
            // The old value was non-NULL, so no replacement was done. Another
            // thread did the initialization out from under us.
            delete new_empty_gurl;
        }
    }
    return *empty_gurl;
}

#else

void EmptyGURLOnce(void)
{
    empty_gurl = new GURL;
}

const GURL& GURL::EmptyGURL()
{
    // Avoid static object construction/destruction on startup/shutdown.
    pthread_once(&empty_gurl_once, EmptyGURLOnce);
    return *empty_gurl;
}

#endif // WIN32

bool GURL::DomainIs(base::StringPiece lower_ascii_domain) const
{
    if (!is_valid_)
        return false;

    // FileSystem URLs have empty host_piece, so check this first.
    if (SchemeIsFileSystem() && inner_url_)
        return inner_url_->DomainIs(lower_ascii_domain);
    return url::DomainIs(host_piece(), lower_ascii_domain);
}

bool GURL::EqualsIgnoringRef(const GURL& other) const
{
    int ref_position = parsed_.CountCharactersBefore(url::Parsed::REF, true);
    int ref_position_other = other.parsed_.CountCharactersBefore(url::Parsed::REF, true);
    return base::StringPiece(spec_).substr(0, ref_position) == base::StringPiece(other.spec_).substr(0, ref_position_other);
}

void GURL::Swap(GURL* other)
{
    spec_.swap(other->spec_);
    std::swap(is_valid_, other->is_valid_);
    std::swap(parsed_, other->parsed_);
    inner_url_.swap(other->inner_url_);
}

size_t GURL::EstimateMemoryUsage() const
{
    //   return base::trace_event::EstimateMemoryUsage(spec_) +
    //          base::trace_event::EstimateMemoryUsage(inner_url_) +
    //          (parsed_.inner_parsed() ? sizeof(url::Parsed) : 0);
    DebugBreak();
    return 0;
}

std::ostream& operator<<(std::ostream& out, const GURL& url)
{
    return out << url.possibly_invalid_spec();
}

bool operator==(const GURL& x, const GURL& y)
{
    return x.possibly_invalid_spec() == y.possibly_invalid_spec();
}

bool operator!=(const GURL& x, const GURL& y)
{
    return !(x == y);
}

bool operator==(const GURL& x, const base::StringPiece& spec)
{
    DCHECK_EQ(GURL(spec).possibly_invalid_spec(), spec);
    return x.possibly_invalid_spec() == spec;
}

bool operator!=(const GURL& x, const base::StringPiece& spec)
{
    return !(x == spec);
}
